* subversion/include/private/svn_wc_private.h
(svn_wc__find_wc_root): new API. Given a path, it return the
working copy root path. If path is not a versioned directory,
The error SVN_ERR_WC_NOT_DIRECTORY will be returned.
* subversion/libsvn_wc/update_editor.c
((svn_wc__find_wc_root): new function. It is implement of
API svn_wc__find_wc_root in svn_wc_private.h
]]]